The Structural Biology Facility provides: a) resources required for crystallographic structure determination, refinement and analysis, b) molecular graphics and computational support for structural biology, c) molecular graphics and computational support for structure-based drug discovery and d) highly specialized resources for macromolecular characterization related to structural biology. The Facility is essential for the research programs of investigators of the Cancer Center who are studying the relationship between macromolecular structure and function or who are using macromolecular structure as the starting point for structure-based drug design. It is a unique resource at Northwestern University that capitalizes on the extensive expertise of a large group of users and the unique access to the synchrotron radiation X-ray source at Argonne National Laboratories. It also serves to nucleate the development of a local community with expertise in structural and computational biology. Such expertise will increasingly be called upon as the structures of more cancerrelated proteins become available. The Structural Biology Facility is, as are its investigators, located on both campuses of Northwestern University, based in the Department of Biochemistry, Molecular Biology and Cell Biology on the Evanston campus, in the Department of Molecular Pharmacology and Biological Chemistry at the Medical School campus, and also at the LS-CAT sector of Advanced Photon Source. Dr. Alfonso Mondragon, a structural biologist at the Evanston Campus, directs the Facility. The Facility consists of four major components: 1) an outstation at the APS that is devoted to state-of-the-art macromolecular crystallography, 2) X-ray diffraction facilities at the Chicago and Evanston campuses to support preliminary and more routine crystallographic experiments, 3) computational facilities at both campuses to support structural determination calculations, both NMR and crystallographic, computational drug-design, and modeling efforts, including advanced graphical visualization and manipulation of models, and 4) a relatively new component which provides automated facilities for setting up and visualizing crystallization experiments and for characterization of macromolecules for structural studies. The distributed nature of the facility reflects the means by which the data collection, computational, molecular visualization, and other scientific resources are networked, and thus integrated, for the structural biology research community at Northwestern.